The invention of this application is an improvement on and a modification of the tone generator construction disclosed in application Ser. No. 814,417 filed July 11, 1977 and application Ser. No. 838,381 filed Sept. 30, 1977, now abandoned both assigned to the assignee of this application. In the construction disclosed in these prior applications, the diaphragm and the electromagnet are independently mounted and retained in the housing and the pole piece portion of the electromagnet is positioned with respect to and spaced from the diaphragm by frictional engagement between the pole piece and the bobbin.